dzhokhar tsarnaev is still in serious condition at beth israel deconess medical center-- sedated, with a tube down his throat, and unable to speak. although massachusetts does not have the death penalty, prosecutors could seek capital punishment at the federal level. >> "given the facts that i've seen it would be appropriate to use the death penalty in this case and i would hope they would apply it in federal court." >> reporter: now, more questions are being raised about the suspects, and if the f-b-i did enough before the bombings. in 2011, the f-b-i says it interviewed the older brother, tamerlan, after russian authorities alerted the u-s government. he then made a six-month trip to russia in 2012,but his exact whereabouts and activites are unclear. >> "the ball was dropped in one of two ways, the fbi missed a lot of things is one potential answer, or our laws do not allow the fbi to follow-up in a sound, solid way." >> reporter: while officials sift through the details, worshippers sought answers in their own way-- gathering at the cathedral of the holy cross sunday to reflect on t